Patent GB-822977-A (GB)
Title: Machines for the manufacture of polishing buffs
IPC: B24D18/00
Filed: 1957-05-09
Abstract: 822,977. Making polishing buffs. TREVENNA, G. R. May 9, 1957 [May 9, 1956], No. 14808/57. Class 60. A machine for assembling polishing buffs comprises a buff-assembly tray 51, Fig. 7, arranged to reciprocate horizontally between two extreme positions over two magazines 42, Fig. 2, containing layers of material, two pick-up and depositing heads 19, 20 which are arranged to reciprocate vertically above the two magazines and are so operated that, while one head is picking up the uppermost layer of material in its magazine, the other head is depositing a layer of material in the tray, and pneumatic means for maintaining each layer in substantially flat condition while it is being deposited. The main features of the machine are substantially the same as those disclosed in Specification 753,960 for assembling a buff comprising superimposed layers each in the form of a plurality of sections. In the present construction in which, as in the prior Specification, the whole cycle is automatic ; empty trays 51 are fed one at a time down an inclined ramp 93 on to a table 78 from which they are pushed in turn by a pneumatic ram 79 on to a turntable 104 carried by a table 76 which is reciprocated by a pneumatic ram 103 between two extreme positions over the magazines 42. The act of pushing an empty tray on to the turntable also discharges a completed tray on to table 78. The trays are held magnetically onto the turntable which is arranged to be indexed at each end of the stroke of the table 76 by a pawl-and-ratchet device so as to provide for staggering of the joints in superposed layers ; the latter effect may, alternatively, be effected by relatively staggering the joints of the material in the two magazines 42. The compartmented magazines 42 containing the material are fed into position beneath the pick-up heads 19, 20 on sliding platforms 118 which are operated by pneumatic rams 115, 116 ; means on the pick-up heads ensures that, as soon as any compartment of a magazine becomes empty, the relevant ram is operated to feed a full magazine into position and discharge the empty one on to a table 124 k. Each pick-up head comprises two spaced plates 21, 22 operable vertically by pneumatic rams 25, 26. The plate 21 carries suspended rods 30 each with a pick-up device at its lower end and also a second set of suspended rods 55 mounting a hollow pressure plate 54 for flattening the material as it is deposited in a tray ; the plate 22 carries one or more suspended rods 52 for stripping material from the pick-up devices as it is deposited in a tray. Each pick-up device, Fig. 8, comprises a channel member 33 which is slidable on rod 30 and carries a slidable ferrule 36 adapted, when the rod is lowered to cause the device to contact a layer of material in a magazine, to actuate a pawl-and-ratchet device 43, 46 to feed a strip of adhesive tape between two drums 40, 48 ; the top layer of material in the magazine is then gripped by the adhesive tapes for raising with the rods 30 and subsequent deposition in a tray 51 and stripping by the rods 52. The pressure plate 54 which has a perforated under face is connected through pipes 61 to a vacuum tank 60 whereby suction is applied to hold the material in flattened condition for its correct deposition in the tray ; a transparent skirt 74 surrounds the pressure plate. Suction is also applied from the tank 60 through pipes 128 to the underfaces of the magazines to ensure that only the topmost layer of material is lifted by the pick-up devices. Means are provided to feed a new tray on to the turntable 104 and discharge a completed tray when the latter has been built to the required thickness and stop the machine should any of the rams not operate correctly or if no fresh tray is available on the ramp 93 for discharge on to the table 78. Chain drives may be used in place of the rams 79, 115, 116. Specification 683,753 also is referred to.